The effects of drilling on revascularization and new bone formation in canine femoral heads with avascular necrosis: an initial study.

In this study, the effects of drilling on revascularization and new bone formation were evaluated in nine dogs with surgically induced avascular necrosis (AVN) of the femoral head. Six animals had holes drilled from the greater trochanter into the femoral head at the time of vascular interruption. Vital fluorescent bone stains were injected immediately postoperatively (calcein green). 6 weeks postoperatively (xylenol orange), and 12 weeks postoperatively (oxytetracycline). In the operative femoral heads, a relative absence of calcein green indicated successful production of AVN. All of the specimens had uptake of oxytetracycline, indicating complete revascularization by 12 weeks postoperatively. Xylenol orange was found throughout the femoral head in the six drilled heads, indicating complete revascularization by 6 weeks postoperatively. Two of the three undrilled dogs failed to show distribution of xylenol orange throughout the femoral head, which indicated incomplete revascularization by 6 weeks postoperatively. In the drill tracts that were identified, calcein green was observed along the full length of the tract, indicating very early new bone deposition in the drill tracts following surgery. These results suggest that a drill hole provides a path for rapid vascular invasion and quickly results in new bone formation in and around the drill tracts. In addition, revascularization takes place more rapidly in canine femoral heads that have been drilled.

Band 3 tyrosine kinase in avian erythrocyte plasma membrane is immunologically related to pp60c-src.

We have identified in the plasma membrane of the chicken erythrocyte a 60-kDa tyrosine-specific protein kinase immunologically related to the transforming protein pp60v-src of Rous sarcoma virus. The erythrocyte protein kinase phosphorylated heavy chains of tumor-bearing rabbit (TBR) antibodies reactive with pp60c-src at tyrosine in immune complex protein kinase assays. The kinase was identified as a 60-kDa protein by [35S]methionine labeling of erythrocytes and by autophosphorylation in immune complexes. The kinase migrated on two-dimensional gel electrophoresis with an apparent pI and molecular mass similar to pp60c-src. A plasma membrane-enriched fraction isolated from chicken red cells contained the majority of the kinase activity. The kinase was solubilized from the plasma membrane by the detergents 0.5% (wt/vol) Na-deoxycholate and 1% (vol/vol) Nonidet P-40. One molar NaCl was much less effective, indicating a strong association of the kinase with the plasma membrane. Incubation of the plasma membrane fraction with [32P]ATP resulted in tyrosine phosphorylation of the anion transport protein band 3. Band 3 phosphorylation was blocked by TBR antibodies, indicating that the kinase recognized by pp60c-src antibodies was responsible for band 3 phosphorylation. These results demonstrate that the avian erythrocyte plasma membrane contains a tightly bound tyrosine-specific protein kinase identical or closely related to pp60c-src and that this kinase is responsible for band 3 phosphorylation in vitro.